Drafting machine



Dec. 19, 1944. v.- B. WALLACE DRAFTING MACHINE 5 Sheets-Sheet l I Original F iied Jan. 9, 1959 nrlliiijiI'liIiHHHIHiiI' miiiiiii'lliiiii;

.ZZraZ. i

ATTORNEY.

.iniIiHiiiHiiinmiiiiilll 1944-v v. B. WALLACE Re. 22,582

DRAFTING MACHINE Original Filed Jan. 9 1939 s sheets-sheet '2 10a .FIGZS. IMAM/Tale 144205. All/1C6 BY- I A ATTORNEY.

Dec. 19, 1944. v. B. WALLACE DRAFTING MACHINE Original Filed Jan. 9, was) s Sheets-sheaf 3 Reissued Dec. 19, 1944 DRAFTING MACHINE Vard B. Wallace, Monrovia, Calif., assignonby mesne assignments, to Vard, Inc., Pasadena, Calif., a corporation of California Original No. 2,226,882, datedDecember 31, 1940,

Serial No. 249,889, January 9, 1939. Application for reissue August 24, 1942, Serial No.

My invention relates to drafting machines and has particular reference to a new and improved construction of the device disclosed in my Patent No. 2,051,115, issued August 18, 1936. This application is a continuation, in part, of my co-pending application, Serial No. 207,0l5,'filed May 10, 1938 and entitled Drafting machine. I

'In the art of drafting, itis the common practice to use drafting machines which will support one or more straight edges or scales in such manner that, thoughthey may be moved to various positions over the drawing board or drawing paper, the straight edges may be maintained at a fixed angle relative to a base line on the drawing board.

Two common types of such machines are in general use, one of which is of the pantograph type including a plurality of parallel bars or rods fixed at one end to a base member to be permanently or detachably secured to the drawing board while the opposite ends of the bars or rods are connected to an articulation plate or frame. The second set of parallel bars or rods extend between and are connected to the articulation plate and a scale or straight edge supporting frame, the fixed base, the articulation plate and the frame defining p-arallelograms so that the frame may be moved to various positions over the drawing board without change of its angular relation relative to a predetermined base line on the board.

The other of these types of machines is known as the band and pulley type wherein pulleys mounted. respectively, on the fixed base, the articulation member, and the scale supporting frame are intercoupled by means of endless metal bands in such manner that the scale supporting frame will maintain a definite angular position relative to a base line on the drawing board regardless of the position of the frame upon the board.

In both of these types of machines it is the common practice to mount the scales or straight edges upon a scale support, which is in turn mounted upon the frame to permit of its rotation relative thereto and to thus permit the straight edges or scales to be set at any desired angle relative to the base line and when so set thereafter maintain that same angular position during all movements of the scales or straight edges over the board.

Protractors are also-usually provided upon the I 31 Claims.

the base line. Again it is common practice in these machines to provide pawls or other spring pressed latching devices receivable in notches or holes when the scales are at certain commonly employed angles relative to the base line and to permit of adjustment of the angular position of the scales by retraction of the pawl, rotation of the scale supporting plate and the insertion of the pawl in a newly selected one of the notches or holes; It frequently occurs, however, that the particular angle at whichit is desired to set the scales or straight edges does not coincide with the position of any of the notches or holes and under such circumstances it is desirable that the pawl or latch be locked in a retracted position and that the scale support be clamped in such desired angular position upon the frame.

One of theprim'ary difliculties which have been encountered in the use of-such drafting machines having adjustment for the angular positions of the scales has been that, due to the construction of the machines, the scope of'rotational movement between the scale supporting plate and the parallel mechanism frame has been limited to a relatively small portion of a complete circle whereas it is frequently desired to move the scales to positions beyond this limit; namely, at any position throughout a complete circle. Again anotherdifilculty which has heretofore been encountered has been that the pawls and releasing devices employed for releasing the pawls from their notches or holes have been so inconveniently and awkwardly located that it has been neces sary for the draftsman using the machine to drop pencils, dividers or other instruments which he is then using and to employ both hands for the adjustment or repositioning of the scales and frame.

It is therefore an object of my invention to provide a mounting for the scales on parallel mechanism drafting machines in which the scales may be rotated through a complete 360 0f rotation relative to the parallelmechanism frame.

Another object of my invention is to provide a device of the character set forth in the preceding paragraph which isequally adaptable to either the parallel bar type of drafting machine and to the band and pulley type machine.

Another object of my invention is to provide a scale support and parallel mechanism frame mounting in which a pawl or latch may be employed to adjustably fix the angular relation between the supportingplate and the frame and inwhich release devices for the latch are so con veniently mounted that a person manipulating 2 eases the machine may with a single hand release the latch and turn or adjust; the scales to the new desired position.

Another object of, my invention is to provide a mechanism of the vcharactensetiorth in the preceding; paragraph" svherein @a :simple docking means is provided'for locking the pawl or'latch in its free position whenever it is desired either to move the scales to some uncommon angle for which no notch or hole is provided, ormwhent it is desired to leave the scales in a condition to be freely rotated relative to thefjparallelrnnech anism frame.

Other objects and advantages of my invention will be apparent from a stuidyt ofttheffcllowingi specifications, read in connectiomw'ltht-the accompanying drawings, wherein:

Fig. 1 is a fragmentary plan view illustrating one form of the protractor head of my invention as being employed on a drafting machine of the endiess-"bandwype; 1

*Fig." Zis'a vertical section'* taleen*substantially along "the line? II- II "cif 1 and-"illustrating the construction of the "protractor 'head*-"shown inFisJ-I;

Fig. "3 is a horizonta1"section-"taken as indicated bythe line of 1 ito "show-'mjdditional details of "construction ofi'the ;protractor l'heaid and release .Jme'cha-nism';

Fig. *4 is *a"=vertical ssection taken I along the line off1=Fig.'- 3 an Sillustrating-aa clamping mechanismmployed iortlockingstheqprotraetor headii in any-r set-position FFigJfEi isea plan' view' 1 mm;- illustr ating"the applicatiomdf aprotraetorihead em- 'I -ig; 9isa irlazh vlew "illustrattlingasstilli lfurther n-Ioclified form of protractor release mechanism ?Fig'. 10 is='a g' lan*-view similar to figfi showing an' aldditional'mddiflcatlon" of i-thei rel'e'ase hrechs 's anisrn-of my inventton;

Fig. 11 is '-a wertieal sectional' view taiten as indicated by the line XI-XI of Fig. lwarfd illustrating'thedtails of -?constmotion form df releasemechanlsmy and 12: is? afragmentarymerspecti-vewievw'showing the construction am d inter-relationship of the controliknob; anfdrleasei lever '.employ'e'd in the" 133m "'of'myfinventionwhichisilllustrated in Figs.

Referring T to the i'drawlngs; "li'have 'ilhistrate'd inFigfLLga typical endlessibanti typeiof .draffting;machine which lnclude's-aypair dfarmsor struts I ,iand ,2, eachi'cf 'Whichis "constructed to include :a -pivotlheali .iat reach ."dflits ends f-heln apartbymn extensible andcontractible 'rod m'ehg anism. The "arm L I includes :aiplvot'rheald fl'a 1'91 one end or the rod i l'b :wmcnrm turn carries the pivotdieaid lc atrits. opposite YAmouriting bracket"?! secured or'clamp'ed upon the edge df'a.

drawing board 4 constitutes a pivotal mounting for arm I, upon which bracket the pivot head Ia of that arm may be rotatably secured for movement in a plane parallel to the surface of the 5 board. A 'p-ulleyj;rigidlysecuredto the bracket 3" constitutes one'of a pairof pulleys'about which an endless band or belt 6 extends, the other pulnley I of the pair being rotatably mounted upon thepivot head lc of arm I. Thus, as arm I is t rlo-tatdiiabout the bracket 3 the pulley 1 will maintaimthe same angular position relative to A hram-L22 likewise includes a pivot head 2a pivotally connected to the head Ic of arm I for i5 rotationrelative thereto in a plane parallel to thdboardyhead ia being mounted at one end of *a rc'd "Zbf the'ropposite end of which carries a pivot head 20.

.wAssecon'd endless band or belt 8 extends about apalr of-pulleyson arm 2, one of these pulleys indicated at' 9 bein'g'rotatably'mounted upon the head ".20 "charm-2 while"the"other"may"be the same ,piilley' I "which forms apart "of "arm '1. Thus, as "either or both of the "arms'or struts I 25 and 2 are="moved';ov.er the boardfthe Pulleyfl I will "always "maintain 'a .fixed angular :position relative to a'base lineon" the board.

"As is If ully'ishown an'd described in 7' myaforementioned patent, No.2,'015 ;115, adjustment or the"tension'exerte'd' upon *theiban'd' 8" is permitted by"forming"the pivotheadswithi'shanks' l'llhaving sockets I I "formed therein to"receive"thefends "of the red "I I1), at least one of vtheisockets having an "adjusting screw I 2' therein""which'"threadedly engages the rod Ibsuch that by rotatingtheirod about its "longitudinal axis' the" effectivespacing of'theypulleysliand t mayi'be changed. 'A'sim'ilar ccnstructio-noexnbodied' in-arm I :maybe used to adjust the tension or the"band 6. "If desired,"a knurled or'hexagonalhandleportion I3 maybe formed upon rods Ib"anc12b"to facilitate'turning them.

It "will be "readily observed that 'theaforementioned pulleys 15, *1 and *9 :and the endless bands Ii and :8 cooperating'therewith function ini'combinatic'n withthe pivoted'jointsof the struts land 2 to maintain thepulley 9 in'afixed angular locationrelativeto 'thepulleyfi "and the 'drawing'board'4 soithat'while thepulley S'may board 4, it Willat alLtimes maintaina' fixedan'gu lar relationship to' the 3b ase' line I4"whilei sodoing and'pulley 9: mayiconstitute a support for scales orstraieht "edges Ito be used inmaking drawings on' tl'leboard '4.

'Ifprcvi'de'a? protractor plate I6' which is securely iratta'ched to 'the :pulley 1 9 "and rotatably suppoi'ts co-axially'therewithfa"'headplate l1 which is provided"with'a'protractor inde'xl8. "The head plate I Tis provided with suitable mounting members I9 and 2D for removably supporting :draftingscales orfstraightiedgesfi I "and"? 2. The-scales f I fand22 fare preferably'disposedat'right'angles relative to eacbhotherf-andthe hea'd plate 'I1 which "carries these straight edges is iipreferably made readilyrotatable Withrespeet 'tothe protractor Hi and pulley 9"attachedthereto,so"that the scales 2| and"22 may bepositionedat'any desired angle'rlative to'a base/line I4 'on the As illustrated in.,Figs..2 'and' j3,"the pulley 9 maybe 'rig'id'ly 'secur'ed'tof'the protractor "plate "FGby providing "a recess 24 therein which'w'illaccommodate thepro'tru'dingmortion of an "atta'chingmeans which, "as""sliown inFi'g. '2, may

be movedto anydesired position on. the-drawing comprise machine screws 25 passed through suitable openings 26 in the body portion of the pulley 9 and threadedly engaged with the protractor plate Hi. The assembled pulley 9 and protractor plate l6 may be secured on a sleeve 21 which extends upwardly from the protractor plate Is by providing a hub 21a for engaging the underside of the protractor plate l6 and a means to be described hereinafter for forcing the pulley 9 and the protractor plate l6 against said hub. An inner race 28 of a ball bearing is preferably mounted on the central portion of the sleeve 21, and an outer race 29 of said ball bearing is rotatably secured to the inner race as by means of balls or rollers 30 and secured in a fixed position relative to a body portion 3| of the shank ID as by providing a press fit between the outer race 23 and a recess 32 provided therefor. I provide a nut 21b which is threaded upon the upper end of the sleeve 21 and arranged to clamp the inner race 28, the pulley 9 and the protractor plate l6 between said nut and the hub 210. so as to securely lock each of these elements in a fixed position relative to each other.

In order that the head plate l1 and the scales 2| and 22 attached thereto may be rotatably mounted with respect to the protractor plate l6 to permit the scales to be adjusted or set in dif fer-ent desired angular positions relative to the base line I4, I provide another sleeve 33 which is inserted within the aforementioned sleeve 21 and adapted to rotate therein. The sleeve 33 is provided with a flanged base portion 34 which is secured to the head plate I1 as by means of suitable attaching means 35 which may be, as illustrated in Fig. 2, headless rivets. The head plate I1 is provided with a circular recess 35 adapted to contain the protractor plate I6 so that the upper surfaces of the protractor plate I and the head plate i1 may lie in the same plane while the body portion of the head plate I1 may pass under the protractor plate l6 so as to establish. the

'sleeve 33 as by providing a mounting plate 38 which may be threadedly engaged with a threaded. upper portion 39 and locked in the desired position by means of jamb nuts 40 and 4|. The control knob 31 may be attached to the mounting plate 38 as by means of machine screws 42 engaging the knob 31 and threadedly engaged with the mounting plate 38. An operator may therefore, by grasping the knob 31, rotate the head plate l1 relative to the protractor plate |6 (protractor plate l6 being in a fixed angular position relative to the base line 23) so as to establish any desired angular relationship between the scales 2| and 22 attached to the head plate I] and the base line 23.

In order that the protractor plate l6 and the head plate I! may be automatically secured in a fixed position relative to each other at certain specified and frequently used angular settings of the scales 2| and 22, and to accurately establish these angular settings without requiring great care in operation, I provide a spring actuated such angular positions and for holding the protrator plate l5 relative to the head plate I1 at such angular positions and for holding the protractor plate IS in such position. This mechanism includes a notch plate 5| which is disposed immediately below the protractor plate I6 and securely attached thereto by'the aforementioned fastening means 25. The notch plate 5| is provided with a plurality of notches 52 disposed about the periphery of the notch plate in such location that when said notches register with a pawl 53, the scales 2| and 22 will occupy one of the aforementioned frequently used angular positions. Such angular positions may include a position in which the scale 22 is disposed parallel to the base line 23 and other positions at angles of 15, 30, 45, and 90 'degrees thereto.

The'pawl 53 is pivotally secured to the head plate l1 as by means o'f a pinor bolt 54 and confined in a recess 54a provided therefor in the head plate IT. A spring 55 is provided, which is arranged to normally urge the pawl 53 toward the notch plate 5| so that'whenever the head plate i1 is rotated to a position in which a notch engaging end 56 of the pawl 53 registers with one of the notches 52, the spring 55 will urge the pawl 53 into engagement with that notch so as to intertie the head plate l1 to the notch plate 5| and the protractor plate I6 attached thereto.

I prefer to locate the pivot point 54 approximately on a line tangential to the notch plate 5| at the point of engagement of the pawl 53 with the notch plate 5| so that any tendency of the head plate I1 and the pawl 53 carried thereby torotate relative to the notch plate 5| will provide nocomponent of force tending to dislodge the pawl 53 from engagement with the notch 52 of the notch plate 5|.

In order that the pawl 53 may be readily and easily disengaged from the notch plate 5| by the draftsman employing the machine and in order that such disengagement may be effected through the draftsmans use of the same hand as he uses to rotate the control knob 31, I provide a mechanism which includes a plunger 51 which is slidably mounted in holes 58 and 59 provided in a downwardly extending flange portion 60 of the control knob 31. The plunger 51 is provided with cylindrical gear rack teeth 6| which are arranged to be operably engaged with similar gear teeth 62 provided in a gear sector 53. The gear sector 63 is attached to a shaft 64 which is inserted within the inner sleeve 33'and is 1'0- tatable relative thereto. The gear sector 63 is attached .to the shaft '64 by means of a nut 65 which operates in conjunction with a threaded end 66 of the shaft 64 to force the sector 63 into intimate engagement with a shoulder 61 provided on the upper end of the shaft 64. The shaft 64 is provided with a horizontal flange portion 61a which is disposed immediately below the previously described flange portion 34 of the inner rotatable sleeve 33.

I provide a connecting link 68 which'is confined in a recess 68a in the head plate l1 and pivotally secured to the flange 6111 as by means of a pivot pin 69 located near the peripher of the flange 51a. The other end of the link 68 is pivotally secured to the notch-engaging end 56 of the pawl 53 as by means of a suitable pivot pin 10.

I prefer to arrange the previously described parts in such a manner that should the plunger 51 be moved'to the left, as illustrated in Fig. 3, to rotate the shaft 64, the link 68 will be moved thereby in such a. direction as to move the pawl 53 away from the notch plate 5| against the about its pivot pin I04.

maintained in a fixed angular position relative to the base line I4 thereof through the pantographic action of the aforementioned parallelogr'ams. The hinge member 16 and its associated pivots H are provided so that the drafting machine may be moved in a direction normal to the surface of the drawing board 4.for the purpose of removing a drawing'therefrom.

As illustrated in Figs. 6 and '7, the protractor head of this embodiment of my invention includes the protractor plate I6 and the head plate II, the latter carrying supporting members I9 and to which are attached the drafting scales or straight edges 2| and 22. In order that the protractor plate I6 may be maintained at a fixed angular position with respect to the base line I4, I securely attach said protractor plate Hi to the body portion 3| of the protractor head frame member 89 as by means of screws or bolts 25. The heads of the screws are included in the recess 24 formed in the body portion 3| and the screws extend through suitable holes 26 and into threaded engagement with the protractor plate I6. It follows therefore that the protractor plate I6 must be maintained in a fixed angular position relative to the base line I4 since the protractor head frame member 83 to which it is securely attached is, as has been previously shown, maintained in such fixed location.

In order that the head plate I1 and the scales 2| and 22 carried thereby may be manually rotated to any desired angular position relative to the base line I 4, I secure the head plate II to the sleeve 33 and attach the control knob 31 thereto in the same manner as described hereinbefore.

In this form of the device of my invention, I also incorporate the spring pressed pawl 53 which is arranged to engage each of the plurality of notches 52 provided in the notch plate 5| disposed immediately below and attached to the protractor plate I6. The mechanism for operating the pawl 53 is similar to that previously described in that it includes the shaft 64 which is operably connected to the pawl 53 by the link 68.

Rotation of the shaft 64 will actuate the link 58 so as to move the pawl 53 out of engagement with the notches 52 against the action of the spring opposing this movement. In this embodiment of my invention, illustrated in Figs. 5

through 8, I prefer to employ an alternative means for rotating the shaft 64. This means may include a lever I03 which is pivotally mounted as by means of a pivot pin I04 in a recess I05 provided in the downwardly depending flange portion 60 of the control knob 31.

The lever I03 is preferably provided with a hand contacting portion I06 which may be of a suitable thermo-plastic material, such as Bakelite, molded about the edge of the lever I03 and arranged to protrude from the horizontal recess I05 so as to provide a smooth and comfortable handle by which the lever I03 may be rotated In order that movement of the lever I03 may rotate the shaft 54, I provide a link II extending between the lever I03 and one end of a bell crank I01 which is secured to the upper end of the shaft 64 as by means of a pair of nuts I08 and I00. The link III may be attached to the bell crank I01 by a pivot pin 0 and to the lever I03 by means of a pivot II2.

It'will be seen that movement of the lever I03 in an inward direction with respect to the the notches 52 in the notch plate 5|. It will be further observed that the action of the spring 55 tending to restore the pawl 53 into a notch engaging position will also rotate the shaft 64 in a direction reverse to that just described so as to return the lever I03 to a non-operated position.

For the reasons hereinbefore stated, I prefer to arrange the mechanism so that the protractor release device may be locked in a released position. This may be accomplished, as illustrated in Figs. 6 and 8, by the employment of a locking plunger I|3 which is slidably mounted in a hole 4 and normally urged upwardly by means of a spring ||5 contained in a recess |I6 provided in the control knob 31 and confined between the bottom of the recess H6 and a knob or thumb piece II'I aflixed to the upper end of the locking plunger H3. The locking plunger 3 is provided at its lower end with an annular recess IIB, the plunger being located in such a position as to lie directly over a notch III-l provided in the outer edge of the lever I03 when said lever is moved to its operated position.

It will be observed that should the plunger II3 be depressed when the lever I03 is moved inward to its operated position, the lower end of the plunger |I3 will be inserted into the notch II9 provided in the plate I03 and thereby prevent the outward movement of the lever I03 as a result of the force of the spring 55. The annular recess H8 is made with a width slightly in excess of the thickness of the lever I03 so that when the plunger H3 is depressed with the lever I03 in its operated position and the lever I03 is then released, the side of the notch |I9 provided therein will engage the annular recess H8 and prevent the spring I|5 from moving the plunger Il3- upwardly to release the lever I03.

It will be observed therefore that this operation will lock the lever I03 and the pawl 53 connected thereto in a disengaged position with respect to the locking plate 5|. It will be further observed that in order to release the looking plunger |I3 it is only necessary to move the lever I03 in the releasing direction and thereby disengage the edge of the notch Il9 from the annular recess II8 to allow the spring 5 to move the locking plunger 3 upwardly into a disengaged position. This type of protractor head may also include the clamping device 151) and the bottom cover plate 'I5.

I have illustrated in Figs. 9 and 12 an alternative method of operating the release mechanism for the protractor head as including a lever I20 which may be used to rotate the shaft 64 and thereby actuate the pawl 53. As illustrated in these figures, I prefer to attach the lever I20 to the shaft 54 as by'means of a suitable key I2I engaging the lever I20 and the shaft 64. The lever I20 is arranged to protrude through a suitable slot I22 provided in the periphery of the control knob 31 so as to have the end thereof disposed exteriorly of said knob and be readily accessible-to a draftsman employing this machine. I provide a notch or finger recess I23 in one side of the lever I20 near the protruding end thereof and provide. a boss or protuberance I24 on the periphery of the con trol knob 31 so that the lever I20 may be acright of the lever I20 to engage the recess I23' provided therein and moving the lever I20 toward the boss I24 by exerting pressure between the thumb1and finger; Inasmuch as -the; lever I20 is keyed-tothe shaft, it=will be observed that such operation will rotate a the shaft 64 and effect the disengagement of '-the pawl '53 from-the notch plate 51- in; the manner previously described. It is, of'course, apparentthat the ae tion of the spring 55 tending to move the pawl into engagement with the notches '52 provided in the notch plate 5-I will=restore=the"lever' I to its non-operated position whenever-it"is;,released by the draftsman.

In order that the lever IZWmaybe locked in an operated position corresponding to the re leased position of the protractorhead; I=prefer to form the previously'describedslot I22 whieh is provided in the peripheryof-the controkknob 31 with a J or bayonet shape-which ineludes a toe portion I25; I prefer-to make the-lever I20 of relatively thin and resilient materialso that when moved to the operated positiom it may be deflected or-sprung downwardly to engage the toe portion I25 of the--J slot 'andbe held thereby in the operated position corresponding to the released position of the protractor head.

Iprefer to form the toe-portion- I25i of-thed shaped slot- I22 withan=undercut portion- I26 adapted to receive: the lever I20 when it is pressed into the locked' position-so as toaprevent the resilience of the lever I28 from disengaging said lever-from thetoeportion' of the J slot.

In Figs. 10 and 11, I 'ha-veillustrated-another alternative form of the protractor releasing mechanism of my-invention-whichwillfind favor in those applications where a* lever protruding fromthe side of the control'knob;-3I-is undesin able. In this modification; I -prefer to eflect the release of the pawl 53--from the-notehplate-i-l in the manner previously described; namely;- byuotating the shaft: Inthis-form of-myinvem tion I prefer to accomplishthis-- by-means=of an auxiliary control knob I21 which mayebe at tached to anextension I28-of the shaft fl by means of nuts I29 and I SlPpositionedabove a-nd below the knob-121:- I=preferto fit the know-I21 into a recess I31 providedin the upper surface of the control knob 31- and tcrprovide afinlshed exterior appearanceof the auxiliary control-"knob I2 I by including the nut I2 9 within a recess I 32 and affixinga snap cover I 33*thereabove.

It will be observed'inthis=form-of-my-invention that the auxiliary-control knob I2=I 'isplaced in a position whereit may bereadily-*and' easily manipulated by a draftsmanemploying this-machine regardless of the position to which the protractor head may. be moved;

It should be notedlthatin-eachbf the-modifications of the -mechanism of my inventiomwhich I have illustrated-herein, therscale's-2lgand 22 and the head plate-- I'Ilto which-theyare affixed are positioned .below the, lowermost portionofvthe mechanism attachedto. the. parallel mechanism regardless of whether said parallel mechanism is of the endless bandtype orxoithe; parallela arm type, and that as a result ofithis construction the scales may be moved to any. desired positionjn a full circle withoutinterfering or; coming into contactwith said, parallel mechanisms 7 It will also be notedthatI;have-;.providedaa number of types of a release 1 devices -.for'; theapro: tractor head, each of which -overcomes:,the: -pris 'mary disadvantages; found; in drafting -machines in current use today; that is: to say,--,thatteach--of the Ie18afl;m h jninl5:Wh10h1I have zipr vided amass is so positioned-and 0f such -type as totereadily operable by a. draftsman using the machine with' out requiring that thedraftsman employ both. hands for this operation, the devices of" my invention each being readily manipulated in conjunction withthe operation of rotating the protractor head by, means of the'same-hand which is employed to effect saidrota-tion'. I have also provideda means forlockingsaid mechanisms-in their-released position; saidmeans :bei-ng readily actuated by the same hand of the operator as is employed'to operate the release mechanismand to rotate the protractor head assembly;

While I have shown and describedthe: preferred embodiment of 'myinvention, I do notdesire tobe limited to -any ofthe details of construction-shownor described herein, except as defined in the appendedclaims.

1. A draftingmachinecomprisinga supporting head adapted -for;free movement above a drawing board in a-plane parallel thereto; frame" means extending-below and rotatably supported by said head; means for maintainingsaid framein fixed angular relationwith respect to said" board irrespective of -movement of" said head and" frame over said-board; a drafting tool below said-head, means rotatablysupporting; said' drafting tool from said head, a handle-positionedabove-said head and secured tosaid drafting-tool for rota: tion therewith, releasable locking means for lock ing said-itool'againstrotation with respectto said frame, control'means-abovethe level ofv said head a for actuating said locking' means; inwhich saidlocking-meansycomprises apaw-l onsaid tool -mov; able; into and out of engagement witha'portion of said frame; means guiding said pawl for move-; mentin -a-fi xed path toWardandaway from said frame, shaftmeans-rotatable-withrespect'to said head, means rotatably, supporting said drafting tool from said headyahandle positioned" above said head and secured to said draftingtool j for rotation therewith, releasable; locking meangfor p fiaidit oli a n t r t t o h espectito said fr me co tr eans bo the l, f a d x 11w or t a i a d c ns.,m,e ns,,.in' which aidiloc ing v means. mpri es-a paw1.10 .1'.said, tool movable intoandout of engagementgwitli a per,-

tionofisaid; frame, ,meanslguiding v said pawl ;for

movement in afixedpath toward and away from said, frame, shaft means rotatable with 1 respect to, said frame, and handlev and ,eXtending ..there be.- tween means, adjacent said handle for{ rotating said shaft: relativeto the; handle, a mechanism for, transmitting rotary motion of said, shaft into reciprocating motion of said pawl, and sp ring means: ur in s d pawl ntoz n o i io 3. A drafting machine comprising ja support;- ne: ea hv a aate a o ree eme m bove, a drawin -b a d ai-n n v f l he e oaframe meanszextendinsgbelow andarotatablx-sllDPorted by said head, means for maintaining said frame in fixed angular relation with respect to said board irrespective of movement of said head and frame over said board, a drafting tool below said head, means rotatably supporting said drafting tool from said head, a handle positioned above said head and secured to said drafting tool for rotation therewith, releasable locking means for tion of said frame, means guiding said pawl for movement in a fixed path toward and away from said frame, shaft means rotatable with respect to said frame and handle and extending therebelocking said tool against rotation with respect to said frame, control means above the level of said head for actuating said locking means, in which said locking means comprises a pawl on said tool movable into and out of engagement with a portion of said frame, means guiding said pawl for between, means adjacent said handle for rotating said shaft relative to the handle, a mechanism for transmitting rotary motion of said shaft into reciprocating motion of said pawl, spring means urging said pawl into locking position, a notched disk included in said frame member having notches at predetermined angular spacings thereon into which said pawl fits to positively restrain said tool in predetermined angular posiitons with respect to said frame, said pawl being slidable on said disk between said notches therein, whereby said spring members are effective to automatically engage said pawl with a notch in said disk when said notch reaches said pawl.

4. A drafting machine comprising a supporting head adapted for free movement above a drawing board in a plane parallel thereto, frame means extending below and rotatably supported by said head, means for maintaining said frame in fixed angular relation with respect to said board irrespective of movement of said head and frame over said board, a drafting tool below said head, means rotatably supporting said drafting tool from said head, a handle positioned above said head and secured to said drafting tool for rotation therewith, releasable locking means for locking said tool against rotation with respect to said frame, control means above the level of said head for actuating said locking means,- in which said locking means comprises a pawl on said tool movable into and out of engagement with a portion of said frame, means guiding said pawl for movement in a fixed path toward and away from said frame, shaft means rotatable with respect to said frame and handle and extending therebetween, gear teeth on said shaft, a rack engaging therewith and extending transversely in said handle for rotating said shaft, and means for moving said pawl between released and engaged positions in response to rotary movement of said shaft.

5. A drafting machine. comprising a. supporting head adapted for free movement above a drawing board in a plane parallel thereto, frame means extending below and rotatably supported by said head, means for maintaining said frame in fixed angular relation withrespect to said board irrespective of movement of said head nd frame over said board, a drafting tool below said head, means rotatably supporting said drafting tool from said head, a handle positioned above said head and secured to said drafting tool for rotation therewith, releasable locking means for locking said tool against rotation with respect to said frame, control means above the level of said head for actuating said locking means, in which said locking means comprises a pawl on said tool movable into and out of engagement with a portween, gear teeth on said shaft, a cylindrical rack engaging therewith and extending transversely" in said handle for rotating said shaft, said rack being rotatable in said handle, and means for locking said rack against longitudinal movement with respect to said handle in response to rotation of said rack in said handle.

6. In a drafting machine, the combination of: a drafting head supported for free translatory movement relative to a. drawing board in a plane parallel thereto; means for maintaining said head in a fixed angular position relative to said drawing board irrespective of said translatory movement; a drafting tool disposed below said head; pivot means mounting said drafting tool on said head for free rotation thereabout; a handle secured to said pivot means and disposed above said head for manually rotating said drafting tool; a pawl on said tool; means mounting said pawl for movement into and out of engagement with said head; shaft means supported for rotary movement relative to said head and relative to said tool; means carried by said handle in a position to be operated by the same hand of an operator as is used to grasp said handle and coupled to move said rotatable shaft; and means coupling said pawl t said shaft for moving said pawl out-of engagement with said head in response to movement of said shaft.

'7. In a drafting machine, the combination of: a drafting head supported for free translatory movement relative to a drawingboard in a plane parallel thereto; means for maintaining said head 'in a fixed angular position relative to said drawing board irrespective of said translatory movement; a drafting tool; pivot means rotatably supporting said drafting tool from said head; a handle secured to said pivot means for manually rotating said drafting tool; a pawl on said tool; means mounting said pawl for movement into and out of engagement with said head; spring means normally urging said pawl into engagement with said head; shaft means supported for rotary movement relative to said head and relative to said tool; means carried by said handle in a position to be operated by the same hand of an operator as is used to grasp said handle and cou pled to movelsaid rotatable shaft; and means inter-engaging said pawl and said shaft for moving said pawl out of engagement with said head in response to rotary motion of said shaft.

8. In. a drafting machine, the combination of a drafting head supported for free translatory movement relative to a drawing board in a plane parallel thereto; means for maintaining said head in a fixed angular position relative to said drawing board irrespective of said translatory movement; a drafting tool; pivot means rotatably supporting said drafting tool from said head; a, handle secured to said pivot means moving said pawl oi en'gagement-I. with said head in response tomcvementzofri'said. shaft.

9. In a drafting: machine, the. combination of:

a drafting head supportedi for free translatory movement relative to adrawing board ain aiplane parallel thereto;- means for.- maintaining said headin afixed angular position relative tosaid drawing. board irrespective-of said" translatory movement; a drafting-tool; pivot means .rotat ably supporting said. drafting: tool from? said head; a handle secured to .saidipivot :means for manually rotating saidv draftingi tool;: a. pawl on said tool; meansmounting said pawl for movement into and out, ofrengagementiwithsaid head; shaft means-supported for rotary move:-. ment relative to said headandrelativeztoi said tool; mean-s carried 'bfy said' handle-for: moving said rotatable shaft comprising. a .bell crank :se.-'

cured to said shaft; a leverpivota-lly secured 'to saidhandle in a positionitosbe movedtby: the same hand of an operator as is used to grasp said'handle, and a-link=coupling-saidleverto said bell crank; and'means'coupling said pawl to said'shaft for'moving: said pawl" out of engagement with.said headinresponse toinove ment of said shaft.

'10. In a drafting machine, the combination I of: a drafting head supportedfor: free translae tory movement relative. to" a drawingv board in I a plane parallelthereto; means for maintaining said head in a fixed angular position relative to said drawing board irrespective -of said trans+ latory movement; a drafting tool; pivot means rotatabl-v supporting said= drafting-:- tool= from said head; a handle securedjto said pivot means 11'. In a drafting machine, the combination of: a draftinghead supported 'for free translatory movement relative to a drawing board in aplane parallel thereto; means 'for maintaining said head in a fixed: angular-position; relative to saiddrawing boardirrespective of -saidtrans latory movement; a draftingtool; pivotemeans rotatably supporting said =drafting' tool *from said head; a handle secured to saidpivot means for manually rotating: said draftingtool; a pawl on said tool; means mounting said Pawl for move:-

ment into and. out of engagement with said head; shaft: means supportedfor rotaryimove ment' relative, to said-head and relative to:said tool; a slot. in said handle; 'atleverr secured to said shaft. and. extendingvthrough. said 'slottfor manually; moving said: shaft; andzmeansa: cou plingsaid pawl? to. said". shafthfor 1 moving said pawl out of engagement 3 with said; head in": re+ sponse to movement of said shaft;

' 12. Incombination with. a. drafting machine which includes a: drafting: head :supported upon aparallel 'mechanism: for: free. translatorywmove ment relative to axdrawing board in 1a .planepan allel thereto and jin a fixed angular position relaa tive ithereto 1 having a: drafting {150.01 piv0tal1y se-r,- curedito; said: head-for manuals rotatiomrelative theretwbm: aaha-ndieacoupled ltofisaid vtool :aanddise posed: above: said; head: and 5 having: apdevice; for securinszsaidztool jagai-nst. pivotal movementirelaitive. twsaidiheadicomnrising aripawlmountedzon said itool fora-movement :between :aspositionengaa in; saidx head-l anda; position 1 disengaged there-: fromn a: pawlcontrol.- deviceincluding: shaft meanstsupportedl for: rotary movement relative to said,sheadiandzrelativetosaid tool; means COLL-f plingZSaidpaWlitQ-one. end-of, said-shaft for-mov ngi: said;- pawl} between: said: engaged \1 and disen:E agedipositionsiiniresponsea-to;.-,movement; of said shaft; controi means for! moving said 5 shaft ,car-

rim 5 byrsaidihandlegin :a position" to he: operated by; the; same; hand 10f an; operator: as is 1 used .to gmsmsaidhandle: andifloupledtOf the other 1 end of said-rotatabley shaft; and; manually operable restraining; means associated with: said. control meanswforsrestrainingi 'said shaftin avposition corresplondings; to, the: disengaged; position? of,- said D I 13; In combination: with l adrafting, machine whjich-g includes a draftingghead I supported upon aeparall-el mechanism for; free translatoryymovementirelativegtoia drawingboard'in a plane par;- allel theretoland inaazfixedangularposition rel ative;-;thereto having adrafting-tool pivotally' secured; to. z said-ahead: for manual. rotation relative theretorbyya; hamllescoupledtto 'saidartool and disposeds: ahoveesaid; head'." and having: a; device. for securing saiditoolsagainst ipivotal movement rel-, ative to. said: head comprisinga pawl mounted onzsaid-atoolzfon movement between a position engaging said head and a. position" disengaged therefrom, a-lpawl control device, including: shaft means .supported' for rotary movement relative tossaid tool; means coupling said shaft to move said pawl betweerilsaid engaged and saididisen gagedipositions; gear teeth'on said shaft; a'gear rack1a b0rein said handleslidably and I-rotatably receivingsaidgea-n rack for disposing said rack in-ia: position engaging-said gear teethand in a position. to \Y be moved l by the :same hand-of an operator: asis -usedfi' to grasp said h'andle;= pin means-extending into'said bore; a-slot in said rackifor receivingthe end of 'said'pin'means; and a shoulder near one-endof saidslot adapted to ban-moved "into engagement with said pin means bywrotarvmovement of "said-rack 'to restrain said ra'clrcin. a: position corresponding tothe disengaged' position of "said: pawl.

In combination with a drafting machine whichxincludes a" drafting head supported upon a: parallel-mechanism for "free translatory movement relative to a drawing board in a plane parallel fthere-to and in a-fixed angular position relativevthereto-having a drafting tool pivotally secured to said head for manual rotation-relative thereto byaha-ndl coupled; to said 'tool'fand disposed-"abovesaidheadand having-a device for securing said-too1 against" pivotal movement relative tdsaid head comprising a pawl mounted .on said' tool'for' movement betweena position tlons; plmnger-meansnarried b'y'said handle; and

lflmeans mounting said plunger means for movement from a disengaged position to an engaged position extending across the-path traversed by .said lever in moving from said released position :to said securing position, whereby movement of said plunger to said engaged position when said lever is in said released position prevents movement of said lever to said securing position.

15. In combination with a drafting machine which includes a drafting head supported upon a parallel mechanism for free translatory movementrelative to a drawing board in a plane parallel thereto and in a fixed angular position relative thereto having a drafting tool pivotall secured to said head for manual rotation relative thereto by a handle coupled to said tool and disposed above said head and having a device for securing said tool against pivotal movement relative to said head comprising a pawl mounted on said tool for movement between a position,

engaging said head and a position disengaged therefrom, a pawl control device including: a slot in said handle; a lever extending through said slot and mounted on said handle for pivotal movement along said slot between a securing position and a released position corresponding, respectively, to said engaged and said disengaged positions of said pawl; means coupling said lever to said pawl for moving said pawl between said engaged and said disengaged positions; and'a shoulder formed in said slot near the end thereof corresponding to the released position of said lever for engaging and holding said lever in said released position.

16. In combination with a drafting machine;

which .includes a drafting head supported upon a parallel mechanism for free translatory movement relative to a drawing board in a plane parallel thereto and in, a fixed angular position relative theretohavin-g a drafting tool pivotally secured to said head for manual rotation relative thereto by a handle coupled to said tool and disposed above said head and havin a device for securing said tool against pivotal movement relative to said head comprising a pawl mounted on said tool for movement between a position engagmanually rotating said drafting tool; a pawl on said tool; means mounting said pawl for move ment into and out of engagement with said head; shaft means below the top of said handle supported for rotary movement relative to said head and relative to said tool; means coupling said shaft to move said pawl out of engagement with said head; a bell crank secured to said shaft; a lever carried-by said'handle in a position to be engaged by the same hand of an operator as is used to grasp saidhandle; means pivotally mounting said lever on said handle for pivotal movement inwardly and outwardly relative to said handle; recess means in the side of said handle for receiving said lever in its inward position; and a link coupling said lever to said bell crank for rotating said shaft in response to pivotal movement of said lever. 18. In a drafting machine head, in combination, a latching plate "relatively-fixed in orientation, a pivot pin supported in the head, a straight edge supporting frame carried by the pivot pin,

ing said head and a position disengaged theretions; a shoulder formed in said slot near the end thereof corresponding to the released position of said lever, whereby said lever may-be moved along said slot to said released position and then flexed to dispose said lever behind said shoulder and prevent a reverse movement of said lever;

and an overhanging toepor'tion associated with said shoulder and disposed in a position to extend over said lever and hold said lever behind said shoulder. I

17. In a drafting machine, the combination of: a drafting head supported for free translatory movement relative-to a drawing board in a plane parallel thereto; means for maintaining said head in a fixed angular position relative to said drawing board irrespective of said translatory movement; a drafting tool; pivot means rotatably supporting said drafting tool from said head; a handle secured tosaid pivot means for carried l'ongitudinally of the pivot pin, an arm on the shaft, power storing means controlling movement of rotation of the shaft, link means between the arm and latch and a plunger in the knob operatively connected eccentrically of the shaft. v '19. In a drafting machine head, in combination, means relatively fixedin orientation, a pivot pin, supported in, the head, a straight edge .supporting, framecarried by the pivotpin, a knob for manual engagement lcarriedby the pivot pin, latching means, between the, frame and the relatively fixed means, a shaft supported in the head, an arm on the shaft,.power storing means C011: trolling movement of rotation of, the shaft, link means between the arm and the latching means, and a plunger .carried by the knob operativelyconnected eccentricallyof the shaft to. rotate said shaft. v 20. In a'drafting machine head, in combination, means relatively fixed in orientation, straight edge supporting means, means to releasably secure the relatively fixed means with the supporting means, coaxial members, operative connections between one of said'members and the supporting means, operative connections between the other of said members and the releasable securing means and means to selectively actuate the respective coaxial members.

21. In a drafting machine, in combination, means relatively fixed in orientation, straight edge supporting means, means to releasably secure the relatively fixed'means with the supporting means, coaxial members, operative connections between one member and the supporting means, operative connections between the other member and the releasable means, manually actuatable means to actuate. one member and a second manually actuatable means to actuate the other member.

22. In a drafting machine, in combination, means relatively fixed in orientation, straight edge supporting means, means to releasably secure the relatively fixed means with the supporting means, coaxial means comprising a first member and a second member, operative connections between the first member and the supporting means, operative connections between the second member and the releasable means, a knob to actuate the first member and a plunger carried by the knob toaotuate the second member,

23. In o drafting machine head, in combination, means relatively fixed in orientation, straight edge supporting means, means to releasably secure the relatively fixed means with the supporti-ngmeans, a pivot pin su ported in the head, said straight edge supporting means being carried by the pivot pin, a knob for manual engagement carried by the pivot pin,- a shaft rotatably carried in the head, actuating connections between the shalt and the latching means, reciprocating means carried by the knob, and operative connections between the reciprocating means and the shatt.

24. In a drafting machine head, in combination, a member relatively fixed in orientation, a straight edge supporting frame, means to, mount said frame for rotation below and with reference to said member, a tubular pivot pin passing through said member, means to: fix said pivot pin to said frame, a hand knob above said mel'nbar, means to fix said knob to said pivot pin, means for latching said frame to said member,

ashaft through said pivotpin controlling said straight edge supporting frame mounted for rotai tlon below and with reference to said member, a. tubular pivot pin extending through said memher and fixed to said frame, a hand knob above a said member and fixed to said pivot pin, means for latchin said frame to said member, a shaft through said pivot pin controlling said latching sagas:

pivot pin provided with apassage' mpported in the head, a straight edge supporting frame carr'ied by the pivot pin, a knob for manual engagement carried by the pivot pin, a rotatable shaft carried in the passage of the pivot pin, latching means between the member relatively fixed in orientation and the frame, means on the shaft at the end adjacent the frame for operating the latching means, and means at the knob end of said shaft for rotating said shaft.

29. In a drafting machine, in combination, means relatively fixed in orientation, straight edge supporting means, means to releasably secure the relatively fixed means with the supporting means, coaxial means comprising a first membet and a second member, operative connections between the first member and the supporting means, operative connections between the second member and the releasable securing means, a knob to actuate the first member, an arm fixed on the second member and a plunger pivoted to the arm'wlthin the knob and extending therewithout for manual engagement to actuate the second member. 30., In a drafting machine head, in combination, means relatively fixed in orientation, a.

straight edge supporting means rotatably mounted on the head, a; hand knob to rotate the straight edge supporting means, a latching plate carried by one of said means, a, latch lever pivotally carried by the other of said means and coactlng with the plate, a reciprocating member means, a lever on said shaft and means carried tion; a belt pulley relatively fixed, in orientation, r

a straight edge supporting frame mounted for rotation below and with reference to said policy, a latchin late carried by said pulley, a tubular pivot pin rotating within the pulley and fixed to said framega hand knob above said pulley and carried bythe pivot pin, means on said frame for latching said irame to said latching plate, a shaft through said pivot pin controlling said latching means and means carried b said knob to. actuate said controlling shaft.

27. In a drafting machine head, in combinatlon, a member relatively fixed in orientation, a pivot pin provided with a passage supported in the head, a straight edge supporting frame car rled by the pivot pin, 9; knob for-manual engagement carried by the pivot' in, a shaft carried in the assage or the pivot pin, latchingmeans between the member relatively fixed in orientation and the frame, means on the shaft at the end adjacent the frame for operating the latching 1 operatively connected with the latch lever, a manually actuatable means carried by the knob extending beyond the horizontal circumference of the knob and movable along said circumference and operative connections between the circumferentially movable member and thereciprocating member converting the circumferential movement of the 1 circumferentially movable member into a movement of translation of the reciprocating member whereby the latch is actuated. I

31. In a drafting machine head, in combination, means relatively fixed in orientation. straight edge supporting means rotatably mounted on the head, a hand knob to rotate the 'tion, a member relatively lined in orientation, a

straight edge supporting means, a latching plate carried by one of said means, a latch lever pivotally carried by the other of said means and coasting with the plate, power storing means to urge the latching lever into coacting relationship with the plate, a reciprocating member operativ'e'ly connected with the latch lever, a manually actuatable means carried by the knob extending beyond the horizontal circumference of the knob and movable along said circumference and oper ative connections between the circumfcrentially movable member and the reciprocating member converting the circumferential movement of the circumferentially movable member into a move"- ment of translation of the reciprocating member whereby the latch is actuated.

. VA'RD B. WALLACE. 

